The present invention relates to an improved friction washer, particularly for use in connection with cleaning plastic chips in a plastic recycling operation. Since the beginning of the environmental movement, recycling has been an important aspect of environmental protection, reducing the need for landfill use. Plastic items, particularly plastic bottles of high density polyethylene or HDPE are commonly used for many household products, such as detergents, dishwashing liquids, and the like. In the recycling process, the various plastics are separated by their polymer type and then chopped into small pieces, referred to herein as plastic chips. The pieces typically are no smaller than ⅛ of an inch in diameter. The chips continue to have residues of their prior use, particularly paper labels, adhesives for paper labels, and ingredients of the vessels which they made up. For the plastic itself to be reused, these debris contaminants needs to be removed.
Friction washers are known which require wash water and the plastic chips to travel uphill, with the water and debris discharging at a downhill location, with the cleaned chips discharging at an uphill location. Prior art devices have left excessive amounts of debris on the plastic chips, even after a large volume of hot water (160 degrees Fahrenheit) has been applied to them and an exorbitant amount of electric power has been consumed to agitate them.
Large volumes of water are particularly undesirable because the water is a contaminant and must be dealt with as a potential hazardous waste and processed to remove contaminants from the water. Heating the water is also undesirable, because of the added energy costs involved.